Question

我是javaFX和FXML的新手，一个星期以来，我试图将一组圆圈（它们是一些GUI指示器）绑定到某种方法上，而没有得到它。

我不完全了解：

我应该在哪里初始化我的圈子？
如何在第一次Main.stage.show之后更新我的GUI？
我应该为此使用动画吗？

更具体地说，我的意图是看一些动画，这意味着看到GUI处于初始状态，然后几秒钟后延迟我希望看到例如第一个圆圈涂成红色。谢谢！

我当前的输出是我的GUI立即更新，并且还出现以下错误：

Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
    at sample.UIController.lambda$changeCircleColor$0(UIController.java:87)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Thread.java:748)
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
    at sample.UIController.lambda$changeCircleColor$1(UIController.java:93)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    at java.lang.Thread.run(Thread.java:748)
יונ 09, 2019 9:06:39 PM javafx.fxml.FXMLLoader$ValueElement processValue
WARNING: Loading FXML document with JavaFX API of version 11.0.1 by JavaFX runtime of version 8.0.191

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.stage.Stage;

import java.io.IOException;
import java.util.ArrayList;


public class Main extends Application {
    public static Stage stage = new Stage();
    public static Parent root = new Parent() {
    };

    /**
     * the main method of the program
     */
    public static void main(String args[]) {

        UIController uiController = new UIController();
        uiController.changeCircleColor();

        Application.launch(Main.class, args);
    }

    public void start(Stage stage){
        this.stage = stage;
        FXMLLoader loader = new FXMLLoader();
        try {
            loader.setLocation(getClass().getResource("resources/UserInterface.fxml"));
            this.root = loader.load();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e){
            e.printStackTrace();
        }
        stage.setTitle("Troubleshooting project");
        stage.setScene(new Scene(root, 900, 700));
        stage.show();
    }

}

在Javafx中正确绑定对象并使其更新？

0 个答案: